Stoker



J. P. NORTON Dec. 26, 1933.

STOKER Filed June 26, 1950 INVENTOR (/AMES R NORTON mmmmMmmmmwmmmmmmmmmmfimwmmmm BY 1m ATT NEY Patented Dec. 26, 1933 warren STA STOKER James P. Norton, Worcester, Mass., assignor to Riley Stoker Corporation, Woreesten Mass a corporation of Massachusetts Application June 26, 1930. Serial No. 463,908

9 Claims. (Cl. 11044) This invention relates to stokers for furnaces, and more particularly to stokers of the underfeed type in which the fresh fuel is forced in beneath the actively burning fuel bed.

Stokers of'this type usually comprise one or more troughs or retorts into which the fuel is introduced by a reciprocating ram or equivalent device. The air for combustion is delivered under pressure through tuyere blocks mounted at the upper margins of the retorts. These tuyre blocks must be fastened firmly in place, and it has been customary in the past to utilize bolts for this purpose. This construction has not proven entirely satisfactory, however, for two men are required to installthe'bolt's, and the bolt threads are so damaged by the heat that the nuts cannot be unscrewed when it is desired to replace the tuyere blocks, and it is necessary-to burn'off the bolts with an'acetylene torch.

It is accordingly'one objectof my invention to provide an improved fastening'means for thetuyre blocks of an underfeedstoker which is so arranged that it will hold the blocks firmly in position andthe blocks can be'easily installed and replaced when necessary- In stokers' of the multiple retort type, which" include a plurality of parallel retorts separated by rows of tuyere blocks. it is sometimes found that the'airfails to penetrate sufficiently into the retorts, and the combustion is to a certain extent concentrated inthe portions of the fuel bed directly abovethetuyere blocks. It has heretofore been proposed to remedy'this difficultyby utilizing so-called plate type tuyere blocks, which comprise web portions provided with ribs on one or both sides to form tuyere openings, the individual blocks being mounted side by side in planes substantially perpendicular to the upper margins-of the retort side walls and the arrangement being such that the jets of air are directed transversely'of the retorts. This construction has proven satisfactory in stokers having stationary tuyere blocks, but has been subjectto difficulties when applied to stokers of the well-known Riley type in which the sides of the retorts are recipr'ocated. 'Thisreciprocating movement is depended upon to feed the fuel and ash toward the rear of the furnace,

and it has been found that when plate tuyere blocks of the usual form are used, the desired feeding action does not occur because the blocks tend to slide throughthe fuel.

It is accordingly a further object of my invention to provide a plate tuyere block construction which will insure a satisfactoryfeeding movement of the fuel and ash when applied to a multiple retort stoker having reciprocable retort side walls. a

With these and other objects in view, as willbe apparent to those skilled in the'art, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

In" accordance with one feature of my lI1V611'.:. tion I provide a tuyre block:which is so arranged that it may be inserted in positionon its support-from one'direction only, and I provide a fastening member which is arranged to be deformed while located between a shoulder on the support and a cooperating portion of the tuyere block, and which when deformed serves to lock the tuyere block to its-support and to' the preferred construction, each tuyere block has an integral projection which at assembly'is located between and below a pair of undercut lugs on the supporting structure, and a metal ring is placed in contact with the projection and forced into such a shape that it contacts with the lugs also and prevents upward movement 30 of the block. When the invention is to be applied to a stokerhaving reciprocal retort sides I utilize plate'type tuyre blocks shaped to pro--' -vide abrupt shoulders facing the rear of the furnace, these shoulders being connected by gradually sloping portions. The blocks are preferably shaped to provide a numberof identical groups eachcontaining a small number 'of blocks, and the blocks within each group being progressively higher toward the rear of the group.

Referring to the drawing illustrating one embodiment of my invention and in which like reference numerals indicate like parts, Fig. 1 is a side view of a stoker applied to a furnace, the parts within the furnace being shownin section on the line 1--1 of Fig. 2;

Fig. 2 is an enlarged section of a portion of the stoker on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged elevation of several tuyre blocks mounted on a supporting bracket;

" Fig. 4 is a section on the line 44 of Fig. 3;

Fig. 5 is an enlarged section on the line 5-5 of Fig. 4; 7 Fig. 6 is an enlarged perspective view of one of the fastening members prior-to use thereof; 1

-*Fig.- '7 is a perspective view of one of the supporting brackets for the tuyere blocks; and Fig. 8 is a detail view of the highest or rear one of the tuyere blocks in a group.

In the drawing I have illustrated my invention 110 as applied to an underfeed stoker of the multiple retort type. This comprises a fuel hopper 10 of suitable construction which is mounted outside of and adjacent to the vertical front wall 11 of a furnace. A plurality of horizontal cylindrical ram casings 12 are mounted beneath the hopper and arranged to receive fuel therefrom. A suitable ram, not illustrated, is arranged to be reciprocated within each ram casing by a rotatable crank shaft 14, as is Well known in this art. This crank shaft is arranged to be rotated at a slow speed to a suitable gear reduction device 16 which may be driven by any desired source of power. The weight of the casings and associated parts.

may be supported on pipe columns '17 which rest on a concrete floor 18.

A plurality of parallel underfeed retorts 20 extend rearwardly from the front wall 11. These retorts are provided with stationary bottom plates 21 which incline downwardly at a slight angle toward the rear of the furnace: The side walls of the retortsare formed by hollow side bars 24 which are arranged to support on theirupper surfaces the tuyere blocks ,25. These tuyere blocks are arranged in rows extending longitudinallyofthe stokerbetween the retorts and they forma supportfor the fuel bed and deliver air thereto.

In theembodiment illustrated I have shown these'side bars as being suitably constructed for horizontal reciprocation. For this purpose each side bar is supported at its forward end on a cylindricalmember, 26 which is 'mounted in a slide bearing 28 forming an integral part of the rain casing; ,Eachside bar is arranged to be reciprocated by; its correspondinglram through a lost motionconnection 30 in a manner well known in this art andfully disclosed in the patent to Riley No. 1,090,651. .At its lower and'rearward end each .side bar is attached to a shoe 32 arranged torslide over the upper plane surface of a base plate 33 which is bolted to a pairof I-beams 35. These-yI-beams extend transversely of the stokerand rest in suitable pockets in the side walls of the furnace as will be well understood.

The .stoker as illustrated is provided with an overfeed grate section36. This may be of any suitable construction and is mounted on the side bars 24 beneath the lower end of-the retort 20. This overfeed grateservesas a tuyere-structure to furnish air for the combustion of any unconsumed'coke which issues from the lower end'of the underfeedretort.

In the rear ofthe overfeed grate 36 I have il-' lustrated a rocker-dump plate 38, the upper and forward end of which is pivotally connected to the shoe 32. The rocker plates rest at their lower ends on rolls iosuitably mounted at the rear ends of horizontal rack bars 41. A vertical bridge wall 43. is'arranged in the rear of the rocker plates and in substantial proximity thereto. 1 The posi tion of the rocker plates 38 in relation to the bridge wall may be adjusted by means of a horizontal-shaft 15 .mounted in suitablebrackets 46' It Will be underarranged to be mounted in a plane substantially perpendicular to the upper margin of the retort. The web portions 56 .of adjacent blocks are spaced apart so that air may flow between them. In order to direct this issuing air in the desired directions and form high velocity jets which will effectively penetrate into the mass of fuel in the retort, I provide spaced ribs 5'? integral with the web :ofeach blockp-and preferablyon both sides thereof. so that the air issuing from the tuyres is d rected These ribs are substantially horizontal.

transversely of the retorts. This tends to make the combustion uniform across the width of the stoker and eliminatesthe relatively inactive portions in the fuel bed which are frequently-found directly above the retorts in a sto-ker of this type. i In order to avoid the sifting of fine fuel between the tuyere blocks, I preferqto so arrange the ribs 57 that the ribs of adjacent blocks overlap "each other, as shown particularly in Fig. 3.

In a stoker of the type illustrated, the recipro- :v eating-movement of the side bars is depended;

upon tofeed the fuel and ash toward the rear of the furnace. In order to assist this feeding.

action,;I-so .shape'the tuyere blocks 25 as to. provide abrupt. fuel pushingshoulders 58'facing the rear of the furnace, these shoulders being.- connected by gradually sloping portions 59. .During the rearward movement of the side bars, the u shoulders-58 grip the fuel and carry'it positively toward the ash dump, and during theforwardv movementof the side bars the slopingportions 59 slide easily through the fuel bed without any appreciable. tendency to transpor-trthe fuel with them.

I prefer to form the shoulders 58 by providing a number of identical groups of blocks, each .con-

taining a small number of blocks. In the embodimentv illustrated; I have shown three blocksin each group,-though it will be clear that under some conditions a larger or smaller number may be desirable; The top of each blockslopes downse wardly at an acute; angle with onev side of the web, and ihe blocks within each group are progressively higher toward the rear of the group, so that the shoulder 58 is provided on: the end a blockofeach group of blocks. -This permits the use of relatively high shoulders without necessitatingsteep connect-ing portions. which .would tend to render the feeding action ineffective. The

end block shown in Fig. .8 has its ribs 57 terminating short of the outer ,edge of the block, but as. shown in Figs. 2 and 3 the ribs on the intermediate blocks extend tothe edgesof the webs55 The tuyere blocks 25 are mounted upon L- shaped supporting members or brackets-61, one of I which. is shown in detail in Fig. '7. Each bracket comprises a relatively high vertical plate 62 and a relatively low vertical plate 63, these parts being joined at their ends by connecting portions 65. A boss'66 is*provided at each end of the bracket, in order that it may be bolted to the upper edge of the side bar. When the parts are assem The brackets may be made of any desiredlength,

. lug and prevent movement of the block. As illusbut I have found that a bracket arranged to support nine tuyere blocks is of a convenient size to manufacture. I

In order to locate-the tuyere blocks properly onthe brackeis and hold them firmly in position, I

provide a plurality of spaced lugs 69 which extend over the opening 67 and toward the retort from the upper edge of plate 62, and a plurality of spaced lugs '70 at the upper edge of plate 63 which extend away from the'retort and toward plate 62. When a tuyere block is assembled'on the bracket, the upper portion '71 of the block overlies and rests upon the upper edge of the plate 62, and the part '73 of the web of the block (Fig. 8) enters for a short distance between the lugs 69, which thus prevent any appreciable lateral movement. A downwardly extending projeciion '74 on the lower end of the block enters between the lugs '70 and by contact with plate (53- prevents the block from moving toward the retort. The lower rib 5'7'rests on the pla" e 63. A thin extension '75 on the thick web of'the block contacts with plate 62 to assist in locating the block properly and provides additional surface area over which the air flows, thus cooling the block. i

With this construction it will be seen that 'a tuyere block can be removed only by lifting it straight up until the projection 74 clears thepla'le 63, whereupon it can be moved horizontally toward the retort. The projections '74 are preferably slightly shorter than the vertical distance between adjacent ribs 57 when the blocks are assembled. This permits any one block to be removed or replaced without disturbing the other blocks. v

In order to lock the tuyere blocks in position, I employ a deformable device adapted to be inserted between a lug on the tuyre block and an overhanging shoulder on the support and the partsare so arranged that when the device has been deformed it will engage the shoulder and the trated, I may provide a horizontally extending projection '77 integral with the web of each tuyre block which at assembly is located between and below a pair of the lugs 69. These lugs are undercut as shown in Figs. 5 and '7, and a fastening member 78 is provided which is arranged to be deformed into contact with the projection '77 and the undercut surfaces of the lugs, thereby preventing upward movement of the block. This member '78 is preferably shaped as a ring which may be somewhat elongated in one direction as shown in Fig. 6. Each tuyere block has a vertical opening 79 through the web directly'above the projection '77 to permit insertion of the fastening ring. In the higher end block shown in Fig. 8, the opening '79 is formed partly as an open channel. dropped into the opening '79 and deformed to a substantially the shape shown in Fig. 5 by means long period it may become so badly burned as to need replacing. I therefore prefer to make the projection '77 relatively weak, so that it may be After the block is in place, the ring' '78 is broken off by driving heavily against the ring: 78, a

The projection is made sufficiently strong to withstand the blows necessary to deform the ring to.

the shape shown in Fig. 5.

It will be seen that with this construction the with a punch and hammer. After this projection has been broken off, the block can be removed.

- tuyere blocks 25 are firmly held in place on the supporting brackets by the fastening members '78,.

and when necessary any individual block can be replaced by a new one without disturbing the adjacent blocks; Fuel is delivered to the retorts from the hopper 10 by means of'reciprocating' rams, and the-fuel and ash in the furnace is positively moved toward the dump plates38 by the propelling action of the reciprocating tuyereblocks 25. The abrupt shoulders 58 prevent the tuyere blocks from sliding through thefuel bed during their rearward movement. The ribs 57 serve to direct the air in jets transversely of the retorts,-so that combustion is substantially uniform across the width of the furnace and the efiiciency is materially increased.

Having thus described my invention, what I a claim as new and desire to secure by Letters Patent is:

1. An underfeed stoker comprising a plurality of parallel underfeed retorts mounted within a furnace and extending toward the rear thereof, tuyere blocks supported at the upper margins of the retort side walls and comprising spacedplates mounted side by side and extending laterally in planes substantially perpendicular to said upper margins, the tuyre blocks being arranged to'de liver air to the fuel in directions transversely of the retorts and the blocks being shaped to provide 4 abrupt fuel pushing shoulders facing the rear of the furnace, and means to reciprocate the tuyere blocks longitudinally of the'retorts and thus positively advance the fuel and ash toward the rear ofthe furnace.

2. An underfeed stoker comprising a plurality of parallel underfeed retorts having reciprocable and comprising spaced web portions mounted side by side in planes substantially perpendicular to said upper margins, the tuyere blocks being arranged to deliver air to the fuel in directions transversely of the retorts and the blocks being shaped to provide abrupt fuel pushing shoulders facingthe rear of the furnace which are connected by gradually sloping portions, and means to reciprocate the retort side walls and thus positively advance the fuel and ash toward the rear of the furnace.

3. An underfeed stoker comprising a plurality of parallel underfeed retorts mounted Within a furnace and extending toward the rear thereof, tuyere blocks supported at the upper margins of the retort side walls and comprising spaced web portions mounted side by side in planes substantially perpendicular to said upper margins V 140 nected by gradually sloping portions, and means to reciprocate the tuyere blocks longitudinally of the retorts and thus positively advance the fuel and ash toward the rear of the furnace.

4. An underfeed stoker comprising a plurality of parallel underfeed retorts mounted within a 150 tuyreblocks supported at the upper margins of the retort side walls and comprising spaced web portions mounted side by side in planes substantially perpendicular'to said upper margins, the tuyre blocks being arranged to deliver air to the fuel in directions transversely of the retorts and so shaped as to provide a number of identical groups each containing acsmall number of blocks, the blocks within each group being progressively higher toward the'rear of the group so as to form an abrupt fuel pushingshoulder on each group which faces the rear of the furnace, and means to reciprocate the tuyere blocks longitudinally of the retorts-and thus positively advance the fuel and ash toward the rear of the furnace.

5. A tuyre structure for a stoker comprising a suporting member having a row of spaced horizontally extending .lugs thereon, a plurality of tuyere blocks mounted on the member and each provided with a horizontally extending projection which at assembly is located close to and beneath a pair of the lugs, and a plurality of fastening devices each arranged to be deformed into contact with one of the projections and the adjacent pair of lugs, said parts being so arranged that the tuyere blocks are held in position by the deformed devices:

6. A tuyere structure for a stoker comprising a supporting brackethaving a pair of horizontally an L-shaped supporting bracket having an opening in its lower portion through which air may flow, a' plurality of spaced horizontally extending lugs on the bracket each having undercut furnace .and extending toward the rear thereof, surfaces, aplurality of tuyere blocksmounted on= the bracket-and each having ahorizontally extending projection locatedbetween :andbelow a pair of the lugs, means preventing the blocks from moving horizontally relative to the bracket,

and a ring in contact with each projection which is deformed to contact with the undercut surfaces of the lugs, thereby preventing the blocks from moving. vertically relative to the bracket.

8. A tuyere structure for'a stoker comprising a supporting bracket having a high vertical plate i and a relatively low vertical plate which are spaced apart to provide an opening for the flow of air, a plurality of spaced lugs extending laterally from the high plate over the opening which have undercut surfaces, a plurality of spaced lugs extending from the low plate towardthe high plate, a plurality of tuyere blocks mounted on the bracket and each having a web portion which en- .block and the undercut surfaces of the corre-- sponding pair of lugs on the high plate.

9. A group of tuyere blocks adapted to be assembled with similar groups and mounted substantially vertically on the side walls of an under feed retort comprising a plurality of plates each of which has a central web and laterally projecting ribs forming air channels, the top edges of the plates sloping gradually towards one end of the group, and the outer face of the highest end platehaving an exposed portion at assembly which forms a fuel pushing shoulder, the vertical faces of the other plates being unexposed.

JAMES P. NORTON; 

